Spark plug



W. C. KRETSCHIVIER.

SPARK PLUG.

APPLICATION FILED IAN. 27. 192|.

Patented Oct. 24, 1922.

Mier I 7^ @Mag Patented @cih 24, i922.

NETE@ STATES WALTER C. KRIETSCHMER, F CHICAGO, ILLINOIS.

i,433,2ili

SPARK PLUG'.

Application led January 27, 1921. Serial No. 440,346.

T o allcohom t may concern Be 1t known that I, WAL'rrm C. KnETsoH- MER, a citizen of the United States, residing at Chicago, in the. county of Cook and State of Illinois, havel invented a new and useful Improvement in Spark Plugs, of which the following is a specification.

This invention relates to improvements in spark plugs, and more especially to that kind of a spar-k plug adapted for use in connection with the ignition of an internal combustion engine( It is of the type of plug adapted to produce two spark gaps in -order to make the ignition of the confined gases in the engine cylinder more certain.

Among the features of my invention is theprovision of means by which the terminais at the/end of the plugmay be readily cleaned without removing the plug from the engine cylinder. The other features of my invention will appear more fully as I proceed with myspecification.

In that forni of plug embodying the features of my invention shown in the accom,

panying drawings, Figure 1 is a vertical sectional view of my improved plug, Figure 2 is a bottom plan view thereof, Figure 3 is a Vertical sectional View of the shell of the plug onl taken as indicated by the line 3 of Fig. 1, igure 4 is a plan view of one of the gaskets used in the construction of the plug, Figure 5 is a horizontal sectional view of the insulating core of the plug taken as in dicated by the line 5 of Fig. 1, and Figure 6 is aA View in side elevation of the end of the core as shown in Fig. 1.

As shown in the drawings, the plug conf Sists of a casing 4, of any desired pattern and construction, formed at one end with the threads 5 adapted to engage threads in a hole in a cylinder of an engine in the usual manner. A shoulder 7 is formed in the casing 4, and at the outer end of the latter it is enlarged and threaded on the inside, as atr 8, to receive the threaded portion 9, of a nut 10. A core 11, of porcelain, or any other suitable insulating material, ...is fitted in the casing 4 as shown. rllhe insulating core 11 has nea-r its center an enlarged cylindrical part indicated by 80, forming the lower flange 12 and upper ilange 13. The core 11 is also provided with an axial central opening 14. The core 11 is placed in the casing with the flange 12 abutting against the shoulder 7, a gasket 81 being interposed therebetween. The nut 10 is screwed into place withits lower edge abutting against a gasket 83 which rests on top of the flange 13. It is obvio-us that by screwing down the nut 10 the core 11 will be held firmly in place in the casing. 'Ihe lower or inner end `of the core 11 is tapered as indicated by 85."

Extending through the hole 14 in the core 11 is a metal spindle 15 having attached to its upper end in any suitable manner the lock nuts 86 and binding construction, adapted post 87 of ordinaryI or attaching a wire thereto. The lower end of the spindle 15 is A curved and bent upwardly to form an electrode 19, the end of the same being indicated by 119. The extremeinner or lower end of the core 11 is slightly enlarged to form a. flange or butto-n 89 having at one point on itszperiplaery a -weelge shaped projection indicated by 90. Surrounding the fiange or but-ton 89 is a metal band or electrical conductor 20 having its edges slightly bent or crimped in around the button as indicated b 91 lin order toprevent displacement. ymbedded in the inner end of the casing 4 is .another electrode 21 comprising a U- shaped wire havin its ends 92 bent upwardly and inserte in the edge offthe casd rif-n the. inside of the casing 4, projecting upwardly from the shoulder 7 is a short pin 93, andthe flange 12 on the core 11 is provided with a recess 94 adapted to accommodate the pin 93. The recess 94 extends slightly more than 180 degrees around the periphery of the flange 12. The gasket 81 is also provided with a notch 95 adapted tol accommidate the pin 93. It will be seen that by this construction, when the nut 10 is slightly loosened, the core 11 may be rotated 180 degrees, the pin 93 acting as a stop against the two ends of the recess 94.

' The electrode 19 is firmly xed in the core 11 and has its end 119 bent upwardly'and away from the projection 90. The recess 94 in the iiange 12 is so formed with respect to the projectian on the end of the core 11, and the pin 93 is so located in the casing4 that when the parts are in the position shown in Fig. -2 the pin 93 will be against one end. of the recess 94; and such recess 'will permit rotation of the core 11 for 180 degrees in a clockwise direction (as viewed in Fig. 2) permitting rotation of the projection 90 so that the metal band 20 where it covers this point as indicated by 99 will rub or brush against the electrode 21, as

indicated by the broken lines. The end 119 of the electrode 19 is turned upwardly and away from the point 90. lit is obvious that by this construction rotation of the core 11 cannot be made to cause contact between the electrodes 19 and 21; such rotation being permitted only through 180 degrees. l

ln the operation of my improved plug, one of the high tension wires of the ignition circuit is lconnected to the terminal`87 and the other is groundedI to the engine in the usual manner. The core 11 is then rotated until the pin 93 stops rotation against either endV of theV4 recess 94. When in this position the parts will be as shown in Fig. 2. The

nut 10 is then tightened down-causing the parts to be securely xed in position. lln use, a spark gap is formed between the end 119 of the terminal 19 Iand the band 20, and

Vanother spark is formed between the band 2O and the terminal 21. lt will be seen thereabove,-until the pin 93 acts as a stop against one end or the other of the recess 94, whereof the invention as disclosed in the appendedclaim, in which it is my intention t0 claim all novelty inherent in my invention as broadly as possible in viewV of the prior art.

What l claim as new, and desire to secure by Letters Patent is:

A spark plug comprising a casing, a rotatable insulating core. therein, an electrode projecting from the core, a second electrode projecting from the casing, an electrical conductor attached to the core and insulatel from both of the aforementioned. electrodes, such conductor having a point adapted to rub the electrode on theA casing upon rotation of thel core, and m'eans for limiting the' rotation of the core to prevent Contact between the irstmentioned two electrodes.

ln 4testimony whereof, I have hereunto set my hand and seal this 25th day of January,

WALTER t. KRETSCHMER. [1.. s] 

